1. Field of the Invention
The present invention relates generally to switching devices for energizing lights, appliances and the like. More particularly, the present invention relates to a self-powered latching relay device using a prestressed piezoelectric element to generate an activation signal for the latching relay. The piezoelectric element and associated signal generation circuitry can be hardwired directly to the latching relay or may be coupled to a transmitter for sending an RF signal to a receiver which actuates the latching relay.
2. Description of the Prior Art
Switches and latching relays for energizing lights, appliances and the like are well known in the prior art. Typical light switches comprise, for example, single-pole switches and three-way switches. A single-pole switch has two terminals that are hot leads for an incoming line (power source) and an outgoing line to the light. Three-way switches can control one light from two different places. Each three-way switch has three terminals: the common terminal and two traveler terminals. A typical pair of three-way switches uses two boxes each having two cables with the first box having an incoming line from a power source and an outbound line to the second box, and the second box having the incoming line from the first box and an outbound line to the light.
In each of these switching schemes it is necessary drill holes and mount switches and junction boxes for the outlets as well as running cable. Drilling holes and mounting switches and junction boxes can be difficult and time consuming. Also, running electrical cable requires starting at a fixture, pulling cable through holes in the framing to each fixture in the circuit, and continuing all the way back to the service panel. Though simple in theory, getting cable to cooperate can be difficult and time consuming. Cable often kinks, tangles or binds while pulling, and needs to be straightened out somewhere along the run.
Remotely actuated switches/relays are also known in the art. Known remote actuation controllers include tabletop controllers, wireless remotes, timers, motion detectors, voice activated controllers, and computers and related software. For example, remote actuation means may include modules that are plugged into a wall outlet and into which a power cord for a device may be plugged. The device can then be turned on and off by a controller. Other remote actuation means include screw-in lamp modules wherein the module is screwed into a light socket, and then a bulb screwed into the module. The light can be turned on and off and can be dimmed or brightened by a controller.
An example of a typical remote controller for the above described modules is a radio frequency (RF) base transceiver. With these controllers, a base is plugged into an outlet and can control groups of modules in conjunction with a hand held wireless RF remote. RF repeaters may be used to boost the range of compatible wireless remotes, switches and security system sensors by up to 150 ft. per repeater. The base is required for all wireless RF remotes and allows control of several lamps or appliances. Batteries are also required in the hand held wireless remote.
Rather than using a hand held RF remote, remote wall switches may be used. These wall switches, which are up to xc2xexe2x80x3 thick, are affixed to a desired location with an adhesive. In conjunction with a base unit (plugged into a 110V receptacle) the remote wall switch may control compatible modules or switches (receivers). The wireless switches send an RF signal to the base unit and the base unit then transmits a signal along the existing 110V wiring in the home to compatible switches or modules. Each switch can be set with an addressable signal. Wireless switches also require batteries.
These remotes control devices may also control, for example, audio/video devices such as the TV, VCR, and stereo system, as well as lights and other devices using an RF to infrared (IR) base. The RF remote can control audio/video devices by sending proprietary RF commands to a converter that translates the commands to IR. IR commands are then sent to the audio/video equipment. The console responds to infrared signals from the infrared remotes and then transmits equivalent commands to compatible receivers.
A problem with conventional wall switches is that extensive wiring must be run both from the switch boxes to the lights and from the switch boxes to the power source in the service panels.
Another problem with conventional wall switches is that additional wiring must be run for lights controlled by more than one switch.
Another problem with conventional wall switches is that the high voltage lines are present as an input to and an output from the switch.
Another problem with conventional wall switches is the cost associated with initial installation of wire to, from and between switches.
Another problem with conventional wall switches is the cost and inconvenience associated with remodeling, relocating or rewiring existing switches.
A problem with conventional RF switches is that they still require an external power source such as high voltage AC power or batteries.
Another problem with conventional RF switches is the cost and inconvenience associated with replacement of batteries.
Another problem with conventional RF switches is that they require high power to individual modules and base units.
Another problem with conventional AC-powered RF switches is the difficulty when remodeling in rewiring or relocating a wall switch.
Accordingly, it would be desirable to provide a switching and/or latching relay device that overcomes the aforementioned problems of the prior art.
The present invention provides a self-powered switching or latching relay device using an electroactive actuator. The piezoelectric element in the actuator is capable of deforming with a high amount of axial displacement, and when deformed by a mechanical impulse generates an electric field. The electroactive actuator is used as an electromechanical generator for generating a momentary signal that actuates a latching/relay mechanism. The latching or relay mechanism thereby turns electrical devices such as lights and appliances on and off.
The mechanical actuating means for the electroactive actuator element should apply pressure to the electroactive actuator element with sufficient force/acceleration to generate an electrical pulse of sufficient magnitude and duration. A switch similar to a light switch, for example, may apply pressure through a toggle, snap action or roller mechanism. Larger or multiple electroactive actuator elements may also be used to generate pulses.
In one embodiment, the electroactive actuator is depressed by the manual or mechanical actuating means and the electrical signal generated by the electroactive actuator is applied directly to a relay switch. In another embodiment of the invention, circuitry is installed to modify the electrical pulse generated by the electroactive actuator. In yet another embodiment, the electroactive actuator signal powers an RF transmitter which sends an RF signal to an RF receiver which then actuates the relay. In yet another embodiment, the electroactive actuator signal powers a transmitter, which sends a pulsed RF signal to an RF receiver which then actuates the relay. Digitized RF signals may be coded (as with a garage door opener) to only activate the relay that is coded with that digitized RF signal.
Accordingly, it is a primary object of the present invention to provide a switching or relay device in which an electroactive or piezoelectric element is used to activate the device.
It is another object of the present invention to provide a device of the character described in which switches may be installed without necessitating additional wiring.
It is another object of the present invention to provide a device of the character described in which switches may be installed without cutting holes into the building structure.
It is another object of the present invention to provide a device of the character described in which switches do not require external electrical input such as 120 or 220 VAC or batteries.
It is another object of the present invention to provide a device of the character described incorporating an electroactive device that generates an electrical signal of sufficient magnitude to activate a latching relay.
It is another object of the present invention to provide a device of the character described incorporating an electroactive device that generates an electrical signal of sufficient magnitude to activate a radio frequency transmitter for activating a latching relay.
Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description thereof.